Title

Authors

Date of this Version

2005

Citation

Mohr, L.C., and Nalepa, T.F. (Editors). 2005. Proceedings of a workshop on the dynamics of lake whitefish (Coregonus clupeaformis) and the amphipod Diporeia spp. in the Great Lakes. Great Lakes Fish. Comm. Tech. Rep. 66.

Abstract

Lake whitefish (Coregonus clupeaformis) were collected for diet analysis from Michigan’s waters of Lake Michigan during 1998-2001. When the benthic amphipod Diporeia spp. was available, it was an important item in the diets of small (<430 mm) and large (>430 mm) lake whitefish. In southern Lake Michigan, the most-common prey consumed in the absence of Diporeia spp. included zebra mussels (Dreissena polymorpha), gastropods, chironomids, and Mysis relicta. In northern regions of the lake, alternative prey included chironomids, isopods, Bythotrephes, and fish. Following the decline of Diporeia spp. in southeastern Lake Michigan between 1998 and 2001, their contribution to the diet of small lake whitefish fell from 57% to 1% (dry weight). The contribution of Diporeia spp. to the diet was similar for small fish captured in nearshore (9-30 m) and offshore (31-46 m) waters. Mysis were more common in the diets of fish collected at offshore stations whereas chironomids and zebra mussels were more common in fish from nearshore stations.